humans smart because of genetic defect?

LONDON, England (Reuters) -- A genetic mutation that occurred 2.4 million years ago could be the reason why modern humans have such big brains and weak jaws, scientists said on Wednesday.

They discovered that a fault in a gene called MYH16 in modern humans happened at about the same time that their skulls started to change in shape from other primates, allowing their brains to increase in size.

But the trade-off was a smaller, less powerful jaw.

"The coincidence in time...may mean that the decrease in jaw muscle size and force eliminated stress on the skull which released an evolutionary constraint on brain growth," said Nancy Minugh-Purvis, a member of the team at the University of Pennsylvania School of Medicine, that made the discovery.

All humans have the MYH16 mutation but other primates, including chimpanzees and macaques, still have the intact gene. Over the past few million years, since the genetic fault occurred, human skulls have grown three times in size and the outwardly elongated jaws have receded.

not to surprising. I saw a study that said that the brains convoluted shape was due to tension between the eyeballs and the occipital lobe during development. There is so much of the body that works on feedback for development that it could simply be cutting back on the muscles increased brain size.

On a side note, I have a genetic defect: a centromere inversion on my (I think) number 14 Y-chromosome (might be number 10 though, can't remember). Apparently no bad effects, though.
*Involuntarily Twitches*

Very interesting. Could explain why my lower teeth have been getting scrunched together as I got older. I've also seen this in many other people. I'd say most people.
Could also explain why wisdom teeth are removed too.

"The mutation is reported in the latest issue of the journal Nature (search), not by anthropologists, but by a team of biologists and plastic surgeons at the University of Pennsylvania and the Children's Hospital of Philadelphia."

Isn't the idea of evolution kind of that there aren't genetic faults, just successful and unsuccessful variations (well, perhaps I'm overstating the case).

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You could look at it that way in a philosophical sense, but as I understand it, an incomplete or otherwise damaged gene can still be said to be flawed...it's just that a flaw can be a successful variation.

I have a theory that nature only selects for intelligence in the human species within a range of slightly above average or less. Basically the idea is that the truly brilliant, genius-level intellects are more likely to spend their time on discoveries and inventions and such, rather than raising families. On the other hand, those at the lower end of the intelligence scale are less likely to engage in family planning, resulting in many more children. This trend is also probably accelerating, at least in developed countries, because the time when everyone was expected to have as many children as possible is now past.

Or, as Harvey Danger so aptly if cruelly put it: "I looked around the world and found that only stupid people are breeding."

Nicely put rueyeet.
But genius does have its price. Genius is invariably linked to eccentricity. An unattractive trait to anyone. Would you want to mate with someone who is brilliant but capricious?
The term 'brilliantly impaired' wasn't coined for no reason. I just wish that education systems could learn to recognize people like this very early and harness their talents before latent neuroses may arise. But alas, education systems are meant to just educate the masses - "McDonalds education" I call it. Tasty and for everybody. Not cater to genius.

to get massively off topic, autism has had several things attributed to it over the years. One is that it is a disease of mainly the wealthy and well educated. The other is that it is an expression of extreme maleness. The engineer thing came out of who was most likely to approach the medical community and subsidize research for autism. In the 20th century, as the not the incidence of autism, but the awareness of it grew, it seemed to be a disease of the wealthy. More recently, it has been found to occur somewhat more indiscriminately. As for the extreme maleness aspect- more males have it than girls. autism society of america's website states:

Quote

The overall incidence of autism is consistent around the globe, but is four times more prevalent in boys than girls. Autism knows no racial, ethnic, or social boundaries, and family income, lifestyle, and educational levels do not affect the chance of autism's occurrence.

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as for the original topic, other studies have shown that other primate infants are born more advanced than human infants, but around age 2 i think, the similarity drops off, as human babies continue to grow, and primate babies, whose skulls seemed to have fused long before human infants' skulls do, really slow down in learning. The recent discovery of the gene is the 'why' aspect of the timing of skull fusing.

I think Wired. I know they had an article about it. There are a lot of similarities between "good" engineering thought processes and autistic behaviour. The discovery of Aspberger's syndrome suggests that autism is truly a disease of gradients where there is a continuum from normal to the full blown autistic who just sits and keens.

I know when I heard about the symptoms of Autism I saw a lot of similarities with myself.

Forgive me but I had to say this - evolution is a bunch of donkey poo. I mean seriously, how on earth could everything fit together so well BY CHANCE? Test this by randomly dropping a bunch of toothpics on a table. Do they line up to make something? Of course not. Same goes here.

Forgive me but I had to say this - evolution is a bunch of donkey poo. I mean seriously, how on earth could everything fit together so well BY CHANCE? Test this by randomly dropping a bunch of toothpics on a table. Do they line up to make something? Of course not. Same goes here.

- iindigo

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Reasoning by anology is the ultimate in poor logic. Evolution does not state that dropping toothpicks on a table will lead to a lined up pattern.

Things don't fit together well by chance. It's millions of years of natural selection. Traits that help survival tend to be passed on; those that don't tend to be killed off. Given a great amount of time for all that to be sorted out, and things start to work together quite well. Oh, and while we're at it, all your emotions are just chemically and biologically induced. And there's no such thing as free will. So you really can't blame me if I hate so many people.

iindigo, all i have to say is this... drop those same toothpicks a few hundred billion times over the course of about 4 billion years, if theres still nothing then your post is valid, if not then dont talk. and either way, if you could see 4 billion years from now, you would see huge natural changes in the human race.

I'm also not entirely clear on the difference between a mutation and merely a change, but I think the point is that the change was drastic and sudden (something got screwed up in a generation), as opposed to gradual lean in one direction or another (like the 2.4 million years of evolution of larger brains after the sudden change that made it possible for those brains to get bigger).

iindigo said:

I mean seriously, how on earth could everything fit together so well BY CHANCE? Test this by randomly dropping a bunch of toothpics on a table. Do they line up to make something?

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Amusing analogy in how utterly unrelated it is. That's like saying "Do you really think the English language developed so effectively by chance? Test this by banging on your keyboard for a few minutes--do the characters make intelligible sentences? No!"

No, like English, the construction of life built up over a very long period of building on existing things, trial, error, adjustment to current circumstances, and the occasional accident. It wasn't conciously planned to end up the way it did, but it's worked out quite well.

Of course, this doesn't necessarily mean that there was no intelligent force behind the construction of the universe, or that humans are merely an accident--if there is an all-powerful being and you give it credit for the creation of all things, surely that being is capable of planning evolution so it produced interesting things as it moves along, or perhaps nudged it in the right direction on occasion.

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